Dehumidifying Device with Temperature Control

ABSTRACT

A dehumidifying device includes a compressor, a heating coil, an expansion valve and a cooling coil which are connected to construct a complete refrigeration cycle. Te dehumidifying device further comprises a condenser connected between the compressor and the heating coil. In such a manner, the condenser has a heat output that is controlled to regulate a temperature in a space, with the dehumidifying device simultaneously controlling the humidity and the temperature in the space.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to an air conditioning technology and, more particularly, to a dehumidifying device.

2. Description of the Related Art

A conventional direct expansion dehumidifying device in accordance with the prior art shown in FIG. 3 comprises a compressor “COM”, a heating coil “HC”, an expansion valve “EXP” and a cooling coil “CC” which are connected to construct a complete refrigeration cycle. In practice, the conventional direct expansion dehumidifying device further comprises an air conditioner unit 1 and an exterior air conditioning space 2 connected with the air conditioner unit 1. The air conditioner unit 1 is divided into an equipment space 10 and an interior air conditioning space 11 for mounting all of the above-mentioned parts of the present invention. Preferably, the equipment space 10 and the interior air conditioning space 11 are integrated into a single space. The interior air conditioning space 11 is provided with a supply fan “SF” which is connected with a supply air outlet “SA” of the exterior air conditioning space 2. The exterior air conditioning space 2 is provided with a return air outlet “RA” which is connected with the interior air conditioning space 11. The exterior air conditioning space 2 is also provided with a humidity sensor “HS”. However, the conventional direct expansion dehumidifying device only has a humidity control function and does not have a temperature control function, so that it is necessary to provide an additional air-conditioning system to control the temperature, thereby increasing the cost.

BRIEF SUMMARY OF THE INVENTION

The primary objective of the present invention is to provide a dehumidifying device with temperature control, so that the dehumidifying device simultaneously controls humidity and temperature in a space.

In accordance with the present invention, there is provided a dehumidifying device comprising a compressor, a heating coil, an expansion valve and a cooling coil which are connected to construct a complete refrigeration cycle. The dehumidifying device further comprises a condenser connected between the compressor and the heating coil. In such a manner, the condenser has a heat output that is controlled to regulate a temperature in a space, with the dehumidifying device simultaneously controlling the humidity and the temperature in the space.

Preferably, the cooling coil includes a first cooling coil and a second cooling coil which are operated alternatingly. The first cooling coil includes a first defrosting unit and a first electric throttle. The second cooling coil includes a second defrosting unit and a second electric throttle. In practice, after the first cooling coil performs dehumidifying and frosting to have a predetermined thickness, the second electric throttle is switched to the second cooling coil, with the second cooling coil performing dehumidifying and frosting, and with the first cooling coil performing defrosting. Thus, the first cooling coil and the second cooling coil are operated successively and periodically to achieve a dehumidifying function under a condition of lower than the dew point of 0° C.

Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a graph showing a pressure versus enthalpy relationship of a conventional refrigeration cycle in accordance with the prior art.

FIG. 2 is a graph showing a pressure versus enthalpy relationship of a refrigeration cycle in accordance with the present invention.

FIG. 3 is a schematic circuit layout of a conventional direct expansion dehumidifying device in accordance with the prior art.

FIG. 4 is a schematic circuit layout of a dehumidifying device in accordance with the preferred embodiment of the present invention.

FIG. 5 is a schematic circuit layout of a dehumidifying device in accordance with another preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a heat exchanger including a refrigerant of a compressor “COM” refrigeration cycle. In the basic refrigeration cycle, the heat exchanger only relates to an evaporator “EVP” and a condenser “CON”. In the present invention, the evaporator and the condenser have different names at different positions, but the primary function (heat exchange function) of the evaporator and the condenser is not changed. For example, the cooling coil “CC” is also an evaporator “EVP”, and the heating coil “HC” is also a condenser “CON”.

Referring to the drawings and initially to FIG. 4, a dehumidifying device in accordance with the preferred embodiment of the present invention comprises a compressor “COM”, a heating coil “HC”, an expansion valve “EXP” and a cooling coil “CC” which are connected to construct a complete refrigeration cycle. The characteristic of the present invention is in that, the dehumidifying device further comprises a condenser “CON” connected between the compressor “COM” and the heating coil “HC”. In such a manner, the condenser “CON” has a heat output that is controlled to regulate a temperature in a space, so that the dehumidifying device simultaneously controls the humidity and the temperature in the space. In the preferred embodiment of the present invention, the condenser “CON” is a water-cooled condenser. Alternatively, the condenser “CON” is an air-cooled condenser.

In practice, the dehumidifying device further comprises an air conditioner unit 1 and an exterior air conditioning space 2 connected with the air conditioner unit 1. The air conditioner unit 1 is divided into an equipment space 10 and an interior air conditioning space 11 for mounting all of the above-mentioned parts of the present invention, including the compressor “COM”, the heating coil “HC”, the expansion valve “EXP”, the cooling coil “CC” and the condenser “CON”. Preferably, the equipment space 10 and the interior air conditioning space 11 are integrated into a single space. The interior air conditioning space 11 is provided with a supply fan “SF” which is connected with a supply air outlet “SA” of the exterior air conditioning space 2. The exterior air conditioning space 2 is provided with a return air outlet “RA” which is connected with the interior air conditioning space 11. The exterior air conditioning space 2 is also provided with a humidity sensor “HS” to detect the humidity and a temperature sensor “TS” to detect the temperature. The condenser “CON” is connected with a proportional control valve “MV-T”, a cooling water inlet valve “CWS” and a cooling water return valve “CWR”. Preferably, the proportional control valve “MV-T” is a two-way valve or a three-way valve. In such a manner, the heat output of the condenser “CON” is controlled to regulate the temperature of the exterior air conditioning space 2, so that the dehumidifying device simultaneously controls the humidity and the temperature in the exterior air conditioning space 2.

In the traditional dehumidifying device, operation of the compressor is controlled by a humidity preset value. In the dehumidifying device of the present invention, operation of the compressor “COM” is controlled simultaneously by a preset humidity value and a preset temperature value that are controlled by a controller. Thus, when the humidity of the exterior air conditioning space 2 does not reach the preset humidity value or the temperature of the exterior air conditioning space 2 does not reach the preset temperature value, the compressor “COM” is operated successively.

In the present invention, the condenser “CON” is added and connected between the compressor “COM” and the heating coil “HC”, so as to control the temperature of the exterior air conditioning space 2 by controlling the heat output of the condenser “CON”. The dehumidifying device of the present invention produces subcooling in the refrigerant system, and the traditional dehumidifying system does not have such a subcooling action. In such a manner, the subcooling of the refrigerant will enhance the dehumidifying (or refrigerating) capability of the refrigerant system.

The first difference between the dehumidifying device of the present invention and the traditional dehumidifying device is in that, the temperature control function is enhanced in a determined space that needs a temperature control, so that it is unnecessary to provide additional air-conditioning equipment, thereby decreasing the cost.

Referring now to FIG. 1, a refrigeration cycle of the traditional dehumidifying device comprises a compression process a−b (by a compressor), a condensing process b−c (by a condenser), a throttling process c−d (by an expansion valve), and an evaporation process d−a (by an evaporator).

In the compression process a−b,

W _(c) =G×(h _(b) −h _(a))

In the condensing process b−c,

Q _(c) =G×(h _(b) −h _(c))

In the throttling process c−d,

h _(d) =h _(c)

In the evaporation process “d−a”,

Q _(e) =G×(h _(a) −h _(d))

The operational balance of the compressor is listed as follow:

Q _(c) =Q _(e) +W _(c)

When Q_(c) and Q_(e) are not balanced (Q_(c)>Q_(e)), the temperature balance in the space is not achieved. Thus, when the traditional dehumidifying device is started, the temperature in the space rises, so that it is necessary to provide an additional air-conditioning system to carry away the residual heat.

The symbols of the above-mentioned equations are described as follow:

W_(c)=power of the compressor=KJ/S(KW)

G=mass flow rate of the refrigerant=KG/S

h=enthalpy of the refrigerant=KJ/KG

Q_(c)=heat output per unit time of the condenser=KJ/S(KW)

Q_(e)=heat input per unit time of the evaporator=KJ/S(KW)

Referring now to FIG. 2, a refrigeration cycle of the dehumidifying device of the present invention comprises a compression process a−b (by a compressor), a condensing process b−c (by a condenser), a throttling process c′−d′ (by an expansion valve), and an evaporation process d′−d+d−a (by a gain of the refrigerant subcooling plus a traditional evaporator).

In the compression process a−b,

W _(c) =G×(h _(b) −h _(a))

In the condensing process b−c,

Q _(c) =Q _(c1) +Q _(c2)

In the throttling process c′−d′,

h _(d′) =h _(c′),

In the evaporation process d′−d+d−a,

Q _(e) =Q _(e1) +Q _(e2)

Q _(e) =G×(h _(a) −h _(d))+G×(h _(d) −h _(d′))

The operational balance of the compressor is listed as follow:

Q _(c) =Q _(e) +W _(c)

(Q _(c1) +Q _(c2))=(Q _(e1) +Q _(e2))+W _(c)

The symbols of the above-mentioned equations are described as follow:

W_(c)=power of the compressor=KJ/S(KW)

G=mass flow rate of the refrigerant=KG/S

h=enthalpy of the refrigerant=KJ/KG

Q_(c)=total heat output per unit time of the condenser=KJ/S(KW)

Q_(c1)=first heat output per unit time of the condenser=KJ/S(KW)

Q_(c2)=second heat output per unit time of the condenser=KJ/S(KW)

Q_(e)=total heat input per unit time of the evaporator=KJ/S(KW)

Q_(e1)=first heat input per unit time of the evaporator=KJ/S(KW)

Q_(e2)=second heat input per unit time of the evaporator=KJ/S(KW)

The second difference between the dehumidifying device of the present invention and the traditional dehumidifying device is in that, the dehumidifying capability of the dehumidifying device of the present invention is enhanced under the same power W_(c) of the compressor.

In the evaporation process d−a of the traditional dehumidifying device as shown in FIG. 1,

Q _(e) =G×(h _(a) −h _(d))

In the evaporation process d′−d+d−a of the dehumidifying device of the present invention as shown in FIG. 2,

Q _(e) =Q _(e1) +Q _(e2)

Q _(e) =G×(h _(a) −h _(d))+G×(h _(d) −h _(d′))

In comparison, the dehumidifying capability (Q_(e)=Q_(e1)+Q_(e2)) of the dehumidifying device of the present invention is greater than the dehumidifying capability (Q_(e)=Q_(e1)) of the traditional dehumidifying device under the same power W_(c) of the compressor. Thus, the subcooling of the refrigerant in the refrigeration cycle enhances the refrigerating (or dehumidifying) effect as indicated by shadow lines in FIG. 2.

The above-mentioned dehumidifying device is available for a condition higher than a dew point of 0° C. When the dehumidifying device is used under a condition lower than the dew point of 0° C., it is necessary to consider the frosting problem.

Referring to FIG. 5 with reference to FIG. 4, a dehumidifying device in accordance with another preferred embodiment of the present invention is available for a condition lower than the dew point of 0° C. The cooling coil “CC” includes a first cooling coil “CC1” and a second cooling coil “CC2” which are operated alternatingly. The first cooling coil “CC1” includes a first defrosting unit “WMD1” and a first electric throttle “MD1”. The second cooling coil “CC2” includes a second defrosting unit “WMD2” and a second electric throttle “MD2”. In practice, after the first cooling coil “CC1” performs dehumidifying and frosting to have a predetermined thickness, the second electric throttle “MD2” is switched to the second cooling coil “CC2”, so that the second cooling coil “CC2” performs dehumidifying and frosting, and the first cooling coil “CC1” performs defrosting, and vice versa. Thus, the above-mentioned procedures are operated successively and periodically to achieve a dehumidifying function under the condition of lower than the dew point of 0° C.

It is appreciated that, when the dehumidifying device is available for the condition lower than the dew point of 0° C., the dehumidifying device replaces the traditional silica gel desiccant wheel system.

Although the invention has been explained in relation to its preferred embodiment(s) as mentioned above, it is to be understood that many other possible modifications and variations can be made without departing from the scope of the present invention. It is, therefore, contemplated that the appended claim or claims will cover such modifications and variations that fall within the scope of the invention. 

1. A dehumidifying device comprising: a compressor, a heating coil, an expansion valve and a cooling coil which are connected to construct a complete refrigeration cycle; wherein: the dehumidifying device further comprises a condenser connected between the compressor and the heating coil; and the condenser has a heat output that is controlled to regulate a temperature in a space, with the dehumidifying device simultaneously controlling the humidity and the temperature in the space.
 2. The dehumidifying device of claim 1, wherein: the cooling coil includes a first cooling coil and a second cooling coil which are operated alternatingly; the first cooling coil includes a first defrosting unit and a first electric throttle; the second cooling coil includes a second defrosting unit and a second electric throttle; after the first cooling coil performs dehumidifying and frosting to have a predetermined thickness, the second electric throttle is switched to the second cooling coil, with the second cooling coil performing dehumidifying and frosting, and with the first cooling coil performing defrosting; and the first cooling coil and the second cooling coil are operated successively and periodically to achieve a dehumidifying function under a condition of lower than the dew point of 0° C. 